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A modified method for simulating non-stationary multi-point earthquake ground motion

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Earthquake engineering and engineering Vibration 2010年第2期9卷 201-211页

作者： Li Minggao,Li Xin and Zhou Jing state key laboratory of Coastal and Offshore {3.,Dalian University of Technology,Dalian 116024,China state key laboratory of Coastal and Offshore {3. Dalian University of Technology Dalian China

A spectral-representation-based algorithm is proposed to simulate non-stationary and stochastic processes with evolutionary power,according to a prescribed non-stationary cross-spectral density matrix. Non-stationary multi-point seismic ground motions at different locations on the ground surface are generated for use in engineering applications. First,a modified iterative procedure is used to generate uniformly modulated non-stationary ground motion time histories which are compatible with the prescribed power spectrum. Then,ground motion time histories are modeled as a non-stationary stochastic process with amplitude and frequency modulation. The characteristic frequency and damping ratio of the Clough-Penzien acceleration spectrum are considered as a function of time in order to study the frequency time variation. Finally,two numerical examples are presented to validate the efficiency of the proposed method,and the results show that this method can be effectively applied to the dynamic seismic analysis of long and large scale structures.

关键词： multi-support excitation spatial correlation power spectrum-compatibility non-stationary ground motion simulation

VARIATIONS ON A THEME BY EULER

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Journal of Computational Mathematics 1998年第2期16卷 97-106页

作者： Kang Feng Dao-liu Wang (state key laboratory of Scientific and {3. Computing, ICMSEC, Chinese Academy of Sciences, Beijing 100080, China) 中科院计算数学与科学工程计算所科学与工程计算国家重点实验室北京

The oldest and simplest difference scheme is the explicit Euler method. Usually, it is not symplectic for general Hamiltonian systems. It is interesting to ask: Under what conditions of Hamiltonians, the explicit Euler method becomes symplectic? In this paper, we give the class of Hamiltonians for which systems the explicit Euler method is symplectic. In fact, in these cases, the explicit Euler method is really the phase how of the systems, therefore symplectic. Most of important Hamiltonian systems can be decomposed as the summation of these simple systems. Then composition of the Euler method acting on these systems yields a symplectic method, also explicit. These systems are called symplectically separable. Classical separable Hamiltonian systems are symplectically separable. Especially, we prove that any polynomial Hamiltonian is symplectically separable.

关键词： Hamiltonian systems symplectic difference schemes explicit Euler method nilpotent symplectically separable

Improved multi-pass fast correlation attacks with applications

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Science China(Information Sciences) 2011年第8期54卷 1635-1644页

作者： ZHANG Bin & FENG DengGuo state key laboratory of Information Security,Institute of {3.,Chinese Academy of Sciences,Beijing 100190,China state key laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing China

In this paper we propose two new algorithms for multi-pass fast correlation attacks on stream *** first algorithm aims at fast symbol-wise decoding in the circumstances that the noise is not very high and we have little resource for *** second algorithm deals with the practical decoding problem in the high noise and limited keystream *** new algorithms are applicable to arbitrary form LFSR and compare favorably to the previously known algorithms in the scenarios under *** applications,we demonstrate new key recovery attacks on one-level Bluetooth E0 and LILI-128,*** 2 3. -bit keystream and 2 28-byte memory,our attack against one-level E0 needs 2 3..1 *** 2 24-bit keystream and 2 24.5 -byte memory,our attack on LILI-128 has time complexity 2 70.6 operations.

关键词： stream cipher fast correlation attacks linear feedback shift register (LFSR) Bluetooth E0 LILI-128

WAVE-CURRENT INTERACTIONS WITH THREE-DIMENSIONAL FLOATING BODIES

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Journal of Hydrodynamics 2010年第2期22卷 229-240页

作者： LIU Zhen TENG Bin NING De-zhi GOU Ying state key laboratory of Coastal and Offshore {3. Dalian University of Technology Dalian 116024China state key laboratory of Satellite Ocean Environment Dyamics Hangzhou 310012 China

A Time-domain Higher-Order Boundary Element Method（THOBEM） is developed for simulating wave-current interactions with 3.D floating *** a Taylor series expansion and a perturbation procedure,the model is formulated to the first-order in the wave steepness and in the current velocity,*** boundary value problem is decomposed into a steady double-body flow problem and an unsteady wave ***-order boundary integral equation methods are then used to solve the proposed problems with a fourth-order Runge-Kutta method for the time *** artificial damping layer is adopted to dissipate the scattering *** from the other time-domain numerical models,which are often focused on the wave-current interaction with restrained bodies,the present model deals with a floating *** numerical results of wave forces,wave run-up and body response are all in a close agreement with those obtained by frequency-domain *** proposed numerical model is further applied to investigate wave-current interactions with a floating body of complicated *** this work,the regular and focused wave combined with current interacting with a truss-spar platform is investigated.

关键词： wave-current interaction floating bodies time-domain simulation Time-domain Higher-Order Boundary Element Method(THOBEM)

Recent advances and key perspectives of in-situ studies for oxygen evolution reaction in water electrolysis

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Green Energy & Environment 2024年第10期9卷 1497-1517页

作者： Yi Wang Zichen Xu Xianhong wu Zhong-Shuai wu state key laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Shijingshan District Dalian National laboratory for Clean Energy Chinese Academy of Sciences

Electricity-driven water splitting to produce hydrogen is one of the most efficient ways to alleviate energy crisis and environmental pollution problems, in which the anodic oxygen evolution reaction(OER) is the key half-reaction of performance-limiting in water splitting. Given the complicated reaction process and surface reconstruction of the involved catalysts under actual working conditions, unraveling the real active sites, probing multiple reaction intermediates and clarifying catalytic pathways through in-situ characterization techniques and theoretical calculations are essential. In this review, we summarize the recent advancements in understanding the catalytic process, unlocking the water oxidation active phase and elucidating catalytic mechanism of water oxidation by various in-situ characterization techniques. Firstly, we introduce conventionally proposed traditional catalytic mechanisms and novel evolutionary mechanisms of OER, and highlight the significance of optimal catalytic pathways and intrinsic stability. Next, we provide a comprehensive overview of the fundamental working principles,different detection modes, applicable scenarios, and limitations associated with the in-situ characterization techniques. Further, we exemplified the in-situ studies and discussed phase transition detection, visualization of speciation evolution, electronic structure tracking, observation of reaction active intermediates, and monitoring of catalytic products, as well as establishing catalytic structure–activity relationships and catalytic mechanism. Finally, the key challenges and future perspectives for demystifying the water oxidation process are briefly proposed.

关键词： In-situ studies Water splitting Oxygen evolution reaction Catalytic mechanism

A NEW GENERALIZED ASYNCHRONOUS PARALLELMULTISPLITTING ITERATION METHOD

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Journal of Computational Mathematics 1999年第5期17卷 449-456页

作者： Zhong-zhi Bai(state key laboratory of Scientific and {3. Computing, ICMSEC, Chinese Academyof Sciences, Beijing 100080, China) 中科院计算数学与科学工程计算所科学与工程计算国家重点实验室北京

For the large sparse systems of linear and nonlinear equations, a new class of generalized asynchronous parallel multisplitting iterative method is presented, and its convergence theory is established under suitable conditions. This method not only unifies the discussions of various existing asynchronous multisplitting iterations, but also affords new algorithmic and theoretical results for the parallel solution of large sparse system of linear equations. Besides its generality, this method is also much more suitable for implementing on the MIMD multiprocessor systems.

关键词： systems of linear and nonlinear equations asynchronous multisplitting iteration relaxed method convergence theory

Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 786-794页

作者： Xu Zhao Naitao Gao Shengcheng wu Shaozhen Li Sujuan wu School of Electrical and Electronic engineering Wuhan Polytechnic UniversityWuhan 430023China Institute for Advanced Materials and Guangdong Provincial key laboratory of Quantum engineering and Quantum Materials South China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China

CsPbX_(3.-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal ***,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic *** a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier *** impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically *** results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap *** optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03.of reference ***,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.

关键词： polyethylene oxide-modified TiO_(2) film low-temperature process CsPbI_(2)Br-based all-inorganic perovskite solar cells photo-voltaic performance

Non-coding RNAs and the acquisition of genomic imprinting in mammals

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Science China(Life Sciences) 2009年第3期52卷 195-204页

作者： ZHANG YiJun & QU LiangHu key laboratory of Gene engineering of the Ministry of Education,{3. key laboratory for Biocontrol,Sun Yan-Sen University,Guangzhou 510275,China key laboratory of Gene engineering of the Ministry of Education State Key Laboratory for Biocontrol Sun Yan-Sen University Guangzhou China

Genomic imprinting,representing parent-specific expression of alleles at a locus,is mainly evident in flowering plants and placental *** imprinted genes,including numerous non-coding RNAs,are located in clusters regulated by imprinting control regions(ICRs).The acquisition and evolution of genomic imprinting is among the most fundamental genetic *** about the transition of mammalian imprinted gene domains from their non-imprinted ancestors,especially recent studies undertaken on the most ancient mammalian clades-the marsupials and monotremes from which model species genomes have recently been sequenced,are of high *** reviewing and analyzing these studies,a close connection between non-coding RNAs and the acquisition of genomic imprinting in mammals is *** evidence comes from two observations accompanied with the acquisition of the imprinting:(i) many novel non-coding RNA genes emerged in imprinted regions;(ii) the expressions of some conserved non-coding RNAs have changed ***,a systematical analysis of imprinted snoRNA(small nucleolar RNA) genes from 15 vertebrates suggests that the origination of imprinted snoRNAs occurred after the divergence between eutherians and marsupials,followed by a rapid expansion leading to the fixation of major gene families in the eutherian ancestor prior to the radiation of modern placental *** in the regulation of imprinted silencing and mediating the chromatins epigenetic modification may be the major roles that non-coding RNAs play during the acquisition of genomic imprinting in mammals.

关键词： genomic imprinting mammals non-coding RNAs

New insight into the role of miRNAs in leukemia

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Science China(Life Sciences) 2009年第3期52卷 224-231页

作者： ZHANG Hua & CHEN YueQin key laboratory of Genetic engineering of the Ministry of Education,{3. key laboratory of Biocontrol,Sun Yan-Sen University,Guangzhou 510275,China key laboratory of Genetic engineering of the Ministry of Education State Key Laboratory of Biocontrol Sun Yan-Sen University Guangzhou China

Recent studies have shown that microRNAs(miRNAs) play an important role in cell differentiation,growth,and death,including the functional study of miRNAs in *** date,miRNA expression profiles in many types of cancers have been identified and miRNA expression signatures associated with types and cytogenetics of leukemia have also been *** evidence has shown that miRNAs could function as either tumor suppressors or oncogenes in cancers such as leukemia,while other miRNAs might be benefitcial for diagnosis and prognosis,predicted to be newly developed *** this review,we summarize the recent progress about miRNAs in leukemia and present a miRNA-mediated network involved in differentiation,proliferation and apoptosis predicted to be the roles of miRNAs in the pathogenesis of leukemia.

关键词： miRNA leukemia regulation network clinical implication